Use LLVM coverage and LCOV genhtml on Windows OS (#131)

cmake/Valgrind.cmake

@@ -0,0 +1,45 @@
+# cmake/Valgrind.cmake
+
+if(DEFINED __OMATH_VALGRIND_INCLUDED)
+    return()
+endif()
+set(__OMATH_VALGRIND_INCLUDED TRUE)
+
+find_program(VALGRIND_EXECUTABLE valgrind)
+option(OMATH_ENABLE_VALGRIND "Enable Valgrind target for memory checking" ON)
+
+if(OMATH_ENABLE_VALGRIND AND NOT TARGET valgrind_all)
+    add_custom_target(valgrind_all)
+endif()
+
+function(omath_setup_valgrind TARGET_NAME)
+    if(NOT OMATH_ENABLE_VALGRIND)
+        return()
+    endif()
+
+    if(NOT VALGRIND_EXECUTABLE)
+        message(WARNING "OMATH_ENABLE_VALGRIND is ON, but 'valgrind' executable was not found.")
+        return()
+    endif()
+
+    set(VALGRIND_FLAGS 
+        --leak-check=full 
+        --show-leak-kinds=all
+        --track-origins=yes 
+        --error-exitcode=99
+    )
+
+    set(VALGRIND_TARGET "valgrind_${TARGET_NAME}")
+
+    if(NOT TARGET ${VALGRIND_TARGET})
+        add_custom_target(${VALGRIND_TARGET}
+            DEPENDS ${TARGET_NAME}
+            COMMAND ${VALGRIND_EXECUTABLE} ${VALGRIND_FLAGS} $<TARGET_FILE:${TARGET_NAME}>
+            WORKING_DIRECTORY $<TARGET_FILE_DIR:${TARGET_NAME}>
+            COMMENT "Running Valgrind memory check on ${TARGET_NAME}..."
+            USES_TERMINAL
+        )
+
+        add_dependencies(valgrind_all ${VALGRIND_TARGET})
+    endif()
+endfunction()